net charge on protein - (Oct/19/2009 )

Hi everyone

I test the interaction between some proteins then I want to know how can I know the net charge on protein.
The PI for thes proteins are 4.74, 5.20, 9.55 and 10.85 while the pH for the buffer that I use is 7.4.

Is there any program or webpage contains info like that.

Thanks a lot

knowing the pI of the protein and the pH of the buffer will tell you whether the net charge will be positive (pH below the pI) or negative (pH above the pI).

determining the actual charge will require other information (such as mobility in an electric field).